The SIP Router Project is the common development framework for projects related to SIP Express Router (aka SER), referred further as x-SER projects. The projects that joined the initiative so far are: SIP Express Router (SER) – the initial project started in 2001 (released under GPLv2 in 2002), Kamailio (OpenSER) – the project started as fork of SER in 2005 and OpenIMSCore – the IMS prototyping project branched from SER.

The latest stable branch of the project is 4.1 – created in December 2013. This code base is used to release Kamailio 4.1.x versions.

Since January 2010, by release of v3.0.0, SIP Express Router (SER) and Kamailio (OpenSER) are the same application, built from same source code. The differences are in database structure used to store subscriber profiles and routing information, which is a matter of what modules are used (e.g., for authentication, user location, a.s.o.). SER refers now to this application used with modules_s/auth_db module while Kamailio is same application but with modules_k/auth_db module.

The main goals for the project are:

bring together the developers and user communities of these projects

reduce maintenance overhead

avoid duplicated efforts in development

develop a core framework that is flexible, extensible and scalable

promote and build a solid open source SIP server project

ensure business credibility

make future forking undesirable, this harms everybody, affects credibility and business

On October 10, 2009, source code of SER and Kamailio was completely integrated in SIP Router GIT repository and branches were created to prepare 3.0.0 releases. On January 11, 2010, Kamailio 3.0.0 was released.

SIP Router Project Facts:

integration has finished – one source code tree for Kamailio and SER

single development environment for Kamailio and SER SIP servers – new features are available in both at once